DE2943960A1 - METHOD FOR SHAPING ELBOW AND DEVICE FOR IMPLEMENTING THE METHOD - Google Patents

Description

'■ *' 29Α3960

Chr. Ragettli Zurich (CH)

METHOD OF FORMING ELBOWS AND EQUIPMENT FOR CARRYING OUT THE METHOD

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The present invention relates to a method for forming pipe bends from straight pipe sections as well to a facility to carry out this procedure.

Basically two processes for the production of pipe bends are known up to now: the bending process and the welding process. In the bending process, a straight piece of pipe is firmly clamped at one end and by means of a bending device bent into a pipe bend, where it may have been previously filled with a suitable medium and both ends has been tightly closed. This method has some disadvantages, such as the relatively high equipment side Effort for the bending machine, the high forces that have to be applied and the decrease in wall thickness on the outside of the arch. The latter in particular impairs or forces the load-bearing capacity of the pipe bend to use a much thicker-walled piece of pipe as the starting material with the result that relatively much a lot of additional material has to be driven, just enough to reach the critical outer wall of the arch to make it resilient.

The welding process is based on a flat piece of sheet metal that has the same dimensions as the development of the Elbow corresponds to. This piece of sheet metal is then rolled up accordingly into the shape of the pipe

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bend and then welded. The disadvantages are, on the one hand, that a considerable proportion of There is waste in the flat sheet metal from which the arch is made, and on the other hand: on the equally considerable, The expenditure on equipment for cutting, rolling up and welding and, last but not least, the large amount of time required when working according to this procedure.

It is now the object of the present invention to propose a method for producing pipe bends which these disadvantages are largely avoided. In particular, it should be achieved that on economic Way, with little expenditure of time and with practically no waste of raw material, pipe bends can be formed with exact dimensions and homogeneous wall thickness all meet the demands that the consumer places on them.

In the method according to the invention, a straight Assumed pipe section that is to be formed into a pipe bend. In order to accomplish the above mentioned task, The process is characterized by the fact that the pipe section is cut off at an angle to the pipe axis at both ends, then step by step Feed is compressed in sections and then the compressed section is calibrated, the inclined upsetting occurring to the pipe axis and perpendicular to the

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Pipe axis calibrating on consecutive Pipe sections is carried out simultaneously.

If 90 pipe bends are to be produced - a common case in practice - the cut of the two pipe ends must be made at an angle of 38.146 _{TO the} normal axis plane. This ensures that after the upsetting has taken place, a pipe bend is available whose flange planes are exactly perpendicular to the pipe axis. It is generally noteworthy that this cutting angle is independent of the pipe diameter; it depends only on the type of bow. This allows pipe sections of various diameters to be prepared for the subsequent upsetting with the cutting device set once.

The upsetting process to form the arch requires significantly smaller forces than with known bending processes must be spent. It can also be proven mathematically that the occurring during upsetting Moments are a lot lower than when bending / which is of course a big advantage in terms of Dimensioning of the devices used for this purpose.

Another object of the invention is to provide a device for carrying out the inventive

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To propose a method that is relatively simple and therefore inexpensive and that is precise and fast work is allowed. According to the invention, this device is distinguished by a plurality of movable upsetting and calibration jaws, as well as by one along an inclined plane on the upsetting and Calibration jaws for movable pipe holder to support one end of the pipe section to be processed.

An advantageous embodiment of this device is characterized in that the upsetting and calibration jaws through a plurality of individual, arranged along a circle segments are formed, which radially against one another are movably attached to segment carriers.

In order to be able to move the upsetting and calibration jaws evenly against each other, the segment carriers are via pairs of articulated levers connected to the frame of the device and are under the action of piston-cylinder units.

To the segment carrier when the piston-cylinder units are actuated, in addition to their displacement movement, a pivoting movement to be carried out, the two articulated levers of a pair can be of unequal length. This can be achieved be that one side of the segment carrier in the area of which the upsetting sections of the upsetting and Calibration segments are located to move a greater amount on each other than the other side of the segment carrier, where the calibration sections of the segments are located.

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According to a further feature of the invention, it is given that the pipe holder has a slide displaceable on an inclined plane, which under the action of a Piston-cylinder unit can be moved back and forth relative to the upsetting and calibration segments.

In the following, the method according to the invention will be described in more detail explained. In the accompanying drawings, an embodiment of the device according to the invention is shown, to which reference is made in the explanation of the method.

Show it:

Fig. 1-6 schematic vertical longitudinal sections through the Set-up during different processing phases of the pipe section.

Fig. 7 shows a section along the line A-A in Fig.l,

and
8 shows a schematic view of pipe sections before processing.

The device consists essentially of the actual compression and calibration device 1 and the pipe holder 2. The upsetting and calibrating device has a cross-sectionally circular frame 3, which by means of a frame 4 is anchored on the ground. On the inside

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of the frame 3 are along the circumference a plurality of Segment carrier anchorages 5 are attached, on which the segment carriers 7 are hinged. The actual compression and calibration segments 8 are arranged on the latter. the Segments 8 are divided into two sections, a compression section 8a and a calibration section 8b.

The segment carriers 7 are under the action of piston-cylinder units 9, which are arranged on the end face of the frame 3. One piston-cylinder unit 9 is in each case assigned to a segment carrier 7 and acts on this via a piston rod 10 and a force transmission member 11. It is easy to see that when the piston-cylinder units 9 are actuated with a resulting Displacement of the piston rods 10 to the left a pivoting of the segment carriers 7 takes place, since the latter are pivotably mounted by means of the pairs of levers 6a, 6b. It follows that the segment carrier 7 on the one hand a Carry out movement towards the center of the device, so approach each other.

As can be seen from FIGS. 1-6, the levers 6a and 6b are not parallel to one another and are also not the same long. The levers 6b, which are articulated to the segment carriers 7 in the area of the compression sections 8b of the segments 8, are slightly longer than the lever 6a, which is in the area of

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Calibration sections 8a of the segments 8 on the segment carriers 7 are hinged. In the retracted rest position of the segments 8, as shown in Fig.l, all segment carriers are 7 in a parallel position to one another, the longer levers 6b are thus pivoted more strongly than the shorter ones Lever. When the piston-cylinder units 9 are actuated, due to these structural features, the Segment carrier 7 is not shifted parallel to one another towards the center of the device, but that The end of the segment carrier 7, which lies in the area of the compression sections 8b of the segments 8, places a larger one Way back than the end in the area of the calibration sections 8a of the segments 8.

The upsetting and calibration segments 8 are expediently mounted so as to be easily exchangeable, so that the device can be attached different pipe diameters can be customized.

As can be seen from FIG. 7, a plurality of Upsetting and calibrating segments 8, twelve in the present example, arranged radially along a circle. In the fully extended position, they are close to one another, the calibration sections 8a with their Inner surfaces enclose a surface that of the outer surface of the pipe bend to be formed.

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As can further be seen from FIGS. 1-6, the pipe holder comprises a base part 15, the surface of which forms an inclined plane 17 which is inclined downwards towards the upsetting device 1 and on which a slide 18 is mounted such that it can move back and forth. A hydraulic or pneumatic piston-cylinder unit is provided for actuating the slide 18.

The carriage 18 has an extension 20 to which a pipe support member 21 is pivotably attached. The latter serves to support the end of the pipe section 14 to be processed.

The process for producing a pipe bend is now as follows:

As can be seen from FIG. 8, a long Pipe 22 cut off the pipe sections 14 to be processed in the required length. They get one at both ends Inclined cut, so that the flanges already run at right angles to the pipe axis when the pipe bend is finished available.

It can be mathematically proven that a certain cutting angle is required for a certain pipe bend, regardless of the diameter of the pipe. If, for example, a 90-bend is to be made, the cut of the pipe pieces must be at an angle οά of 38.146 ° to the axis

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normal planes of the pipe take place. With a 4 5 ° bend, the angle * L = 21.44 °. This allows the pipe pieces to be cut off from a long pipe with practically no waste, as the upper illustration in FIG. 8 shows.

Now the prepared pipe section 14 is placed on the pipe support member 21 on the carriage 18 and so far against the The upsetting and calibration device 1 is displaced until the pipe edges touch the upsetting sections 8b of the segments 8. This situation is shown in Fig.l. Then the The piston-cylinder units 9 are actuated, causing the segments 8 to move together and thus upsetting the pipe section 14 causes. As can be seen from the drawing, the upsetting does not take place perpendicular to the pipe, but to a certain extent Angle to the pipe axis that is less than 90. Thus, the elliptical cross-section seen in the direction of compression becomes of the pipe is gradually deformed into a circle.

As soon as the segments 8 have reached their fully extended position, the piston-cylinder units 9 are in Actuated in the opposite direction, which causes the segments 8 to retreat. Thereafter, the pipe section 14 is further against the device 1 is advanced until the pipe edge again abuts the segments 8. Alsdp.nn are the segments 8 again extended in order to compress the next section of the pipe section 14.

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These processes are repeated gradually, with an initial section of the tube 14 gradually becoming one Deformed arch. Now we have the situation according to Fig. 2 achieved.

Up to this point in the process, only one compression of the pipe section 14 has been carried out, with the help of of the upsetting portions 8b of the segments 8. In the following The compressed starting section of the pipe section 14 is further processed under the effect of the calibration sections 8a of the segments 8 are calibrated, which gives the pipe bend its exact shape in terms of bend and roundness.

For this purpose, the segments 8 are moved back again, the pipe section 14 is advanced further and the piston-cylinder units 9 actuated again for the purpose of bringing the segments together. At the same time, on the one hand, the previously Compressed initial section of the pipe section 14 calibrated under the action of the calibration sections 8a, while on the other hand the following pipe sections are compressed under the action of the compression sections 8b of the segments 8. this happens, as already described above, with gradual advance of the pipe section 14 with alternating advance and moving back the segments. This is now the situation according to FIG. 3.

As already mentioned in the description of the construction of the device, the levers 6b are longer than the levers 6a, so that

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When the segments 8 are actuated, the sections 8b cover a greater distance than the sections 8a. The reason for this is to be seen in the fact that the upsetting process over a greater distance with less force must take place as the calibration process, in which high forces are required along a short path. The proposed Solution allows these requirements to be met with an astonishingly simple construction.

After half of the pipe bend has been formed (Figure 3), the end of the pipe section 14 is removed from the support member 21 and the carriage 18 is withdrawn with the aid of the piston-cylinder unit so that the pipe section can be pivoted downwards, namely in Case of a 90 pipe bend by 22.5 ° (Fig. 4). The remaining pipe sections are then processed in a similar manner with simultaneous upsetting and calibration (FIG. 5) until the situation according to FIG. 6 is reached, where the last, just compressed section of pipe 14 is calibrated with the aid of segment sections 8a. This completes the machining of the pipe section 14, the segments can be moved back and the finished pipe bend can be removed from the device 1.

The method according to the present invention allows extremely efficient work, the device used for this being of simple and robust construction. There is no need to use a calibration mandrel inside the pipe; nevertheless, the pipe bends formed in this way are exactly round and of uniform wall thickness.

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Claims (8)

Claims lJ method of producing a pipe bend from a straight pipe piece, characterized in that the pipe section obliquely both ends cut off to the pipe axis, then partially compressed under peck feed and anschllessend the upset portion is calibrated, wherein the oblique to the tube axis taking place upsetting and the perpendicular to the tube axis taking place Calibration is carried out simultaneously on successive pipe sections. 2. Device for performing the method according to claim 1, characterized by a plurality of movable ones Upsetting and calibration jaws as well as by one along an inclined plane onto the upsetting and calibration jaws too movable pipe holder to support one end of the pipe section to be processed. 3. Device according to claim 2, characterized in that the upsetting and calibration jaws by a plurality of individual segments arranged along a circle are formed, which are radially movable relative to one another on carriers are attached. 130021/0054 ORIGINAL INSPECTED 4. Device according to claim 3, characterized in that the segment carrier is connected to the frame via pairs of articulated levers are connected to the device and are under the action of hydraulic piston-cylinder units. 5. Device according to claim 4, characterized in that the two articulated levers of a pair are of unequal length, so that when confirming the piston-cylinder units, the segment carriers, in addition to their displacement movement, have a Perform swivel movement. 6. Device according to one or more of claims 2-5, characterized in that the segments, in the feed direction seen of the pipe, have an upsetting section and then a calibration section. 7. Device according to one or more of claims 2-6, characterized in that in the area of the upsetting sections the levers lying in the segments are longer than the levers lying in the area of the calibration sections, so that the upsetting sections move towards one another by a greater amount than the calibration sections. 8. Device according to one or more of claims 2-7, characterized in that the pipe holder on one an inclined plane has slidable carriage under the action of a piston-cylinder unit relative to the Upsetting and calibration segments can be moved back and forth. 130021/005 *